This current sensor board is based on the Allegro ACS712ELCTR-20A bi-directional hall-effect current sensor chip that detects positive and negative flowing
currents in the range of minus 20 Amps to positive 20 Amps. The board operates at 5V DC and the current flow through the sensor is converted to an output
voltage starting at 1/2Vcc (or 2.5V) for no current flow and moves up 100mV per amp for positive current or down -100mV per amp for negative current.
The output voltage at +2 amps would be (2.5V + (0.1 * 2)) = 2.7 V
The output voltage at -5 amps would be (2.5V - (0.1 * 5)) = 2.0 V